A protein that slows aging in mice and other animals also protects against the ravages of a high-fat diet, including diabetes, according to a new MIT study. MIT biology professor Leonard Guarente ’74 discovered SIRT1’s longevity-boosting properties more than a decade ago and has since explored its role in many different body tissues. In his latest study, appearing in the Aug. 8 print edition of the journal Cell Metabolism, he looked at what happens when the SIRT1 protein is missing from adipose cells, which make up body fat.